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Finding the Fourth Proportional to 1.89, 2.61 and 1.28

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Solution

The fourth proportional to 1.89, 2.61 and 1.28 is: 1.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1.89 : 2.61 = 1.28 : x
  2. Step 2: Convert to fraction form
    1.89/2.61 = 1.28/x
  3. Step 3: Cross multiply
    1.89x = 2.61 × 1.28
  4. Step 4: Simplify right side
    1.89x = 3.33
  5. Step 5: Solve for x
    x = 3.33/1.89
  6. Step 6: Final answer
    x = 1.77

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.